Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
  • B07C5/36—Sorting apparatus characterised by the means used for distribution
  • B07C5/363—Sorting apparatus characterised by the means used for distribution by means of air
  • B07C5/367—Sorting apparatus characterised by the means used for distribution by means of air using a plurality of separation means
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
  • A24B1/00—Preparation of tobacco on the plantation
  • A24B1/04—Sifting, sorting, cleaning or removing impurities from tobacco
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
  • B07C5/34—Sorting according to other particular properties
  • B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
  • B07C5/3422—Sorting according to other particular properties according to optical properties, e.g. colour using video scanning devices, e.g. TV-cameras
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
  • B07C5/36—Sorting apparatus characterised by the means used for distribution
  • B07C5/361—Processing or control devices therefor, e.g. escort memory
  • B07C5/362—Separating or distributor mechanisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
  • B07C5/36—Sorting apparatus characterised by the means used for distribution
  • B07C5/363—Sorting apparatus characterised by the means used for distribution by means of air
  • B07C5/365—Sorting apparatus characterised by the means used for distribution by means of air using a single separation means
  • B07C5/366—Sorting apparatus characterised by the means used for distribution by means of air using a single separation means during free fall of the articles
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/85—Investigating moving fluids or granular solids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C2501/00—Sorting according to a characteristic or feature of the articles or material to be sorted
  • B07C2501/0081—Sorting of food items
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S209/00—Classifying, separating, and assorting solids
  • Y10S209/906—Pneumatic or liquid stream feeding item

Definitions

• This invention relates to automated bulk inspection and processing systems and, in particular, to multi-band optical inspection and sorting of light-weight articles, such as stripped-leaf tobacco or laminae, tobacco stems, and re-claimed tobacco.
• Automated bulk optical processing equipment can perform a variety of tasks such as, for example, inspecting or sorting bulk articles including raw or processed fruit, vegetables, wood chips, recycled plastics, and other similar products.
• the articles may be classified according to size, color, shape, or other qualities.
• Modern bulk optical processing equipment can rapidly classify and separate very large quantities of such articles into numerous categories.
• Such equipment typically includes a conveyor system for moving the articles past an inspection station where cameras or other detection devices examine the articles as they pass through an inspection zone.
• the inspection station sends signals to a sorting or treatment station where the articles are sorted or otherwise treated by category. For example, defective or foreign articles may be removed from the flow of articles carried by the conveyor system.
• Rapid inspection or sorting of large quantities of articles typically requires high-speed conveyor systems such as, for example, conveyor belts with widths of two to six feet (0.6 to 1.8 meters) that convey the articles at speeds of over 17 feet per second (5 meters per second).
• a problem conveying articles at such speeds is that light-weight articles are relatively unstable and tend to roll, tumble, bounce, and collide with one another. Unstable articles carried by a high-speed conveyor system are difficult to inspect, sort or otherwise process for at least two reasons.
• automated bulk optical processing equipment includes cameras or other optical detectors that optically determine selected characteristics of the articles (e.g., size, color, and shape).
• the rolling, tumbling or bouncing of an article typically diminishes the clarity with which an image of the article is generated, thereby decreasing the accuracy and reliability of the optical information about the article.
• rolling could cause a cubic article to appear round, or an article with differently colored regions could appear to have a single mixed color.
• unstable articles can move laterally and/or longitudinally relative to direction of conveyor belt travel. Lateral article movement is undesirable because it misaligns the articles as they pass from the inspection station to the processing station, thereby resulting in incorrect processing.
• longitudinal article movement along the direction of belt travel causes effective speed differences that place the articles in temporal misalignment for subsequent processing operations.
• Some articles have increased susceptibility to unstable motion on a conveyor, such as light-weight articles and articles of low and non-uniform density.
• Particular examples of such articles include stripped-leaf tobacco or laminae, tobacco stems, and re-claimed tobacco.
• Other examples include undesirable debris such as, for example, feathers, paper, cardboard, plastic, string, rope, dirt, twigs, stones, insects, animal parts, and rubber that may incidentally be included within the acceptable articles. As a consequence, these types of articles are difficult to inspect and sort accurately at high speeds.
• the successful operation of the sorter or processor depends on the products being propelled along the known trajectory.
• the processor notes the exact position of the articles as they pass by and can separate defective or undesirable articles from the volume of acceptable articles.
• This type of system has been successful for articles having a relatively high mass. Articles with high mass are able to maintain their velocity in-air as they are projected from the belt and continue along their predicted trajectory.
• Another attempt to stabilize articles as they are moved along a conveyor belt is the use of a second counter-rotating conveyor belt located above and close to the conveyor belt on which the articles are positioned. Instead of blowing air through a hood that encloses the conveyor belt, the second counter-rotating conveyor belt creates a flow of air in a direction generally parallel to the direction of travel of the articles.
• the flow of air generated by the second counter-rotating conveyor belt has a velocity about the same as the article-conveying belt to reduce any aerodynamic resistance that would otherwise bear against the articles.
• One example of such a system is the Tobacco Scan 6000 manufactured by Elbicon located near Brussels, Belgium.
• Another problem with existing systems is inadequate illumination, detection, and sorting of the articles and, in particular, tobacco products that may include black butyl rubber particles, tobacco-stained latex rubber glove debris, brown cardboard, red cardboard, green paper, and blue plastic rope.
• the black butyl rubber particles may be contaminants from the rubber-wrapped piping systems that transport cooling water in tobacco processing facilities, or they may be intentionally added to the particle flow to test the inspection and sorting capabilities of the system.
• the tobacco-stained latex rubber glove debris contaminates the tobacco products as a result of handling by latex-gloved human laborers.
• Unfortunately because these particular rubber particles are so visibly similar to tobacco products, that are difficult to detect with present inspection systems.
• the other contaminants are bits and pieces of containers and packaging employed in transporting and storing the tobacco products. Because of their colors, conventional sorting techniques render some of them difficult to distinguish from the good tobacco products.
• An object of this invention is, therefore, to provide an improved conveyor for use with automated bulk processing equipment.
• Another object of this invention is to increase stability of light-weight articles as they are carried on and projected in-air from such conveyors.
• a further object of this invention is to provide such a conveyor that is capable of allowing increased accuracy in optical processing of light-weight articles and articles of low and non-uniform density.
• Still another object of the invention is to provide a system with multi-spectral illumination and sorting of the articles and, in particular tobacco products.
• An off-belt stabilizing system of this invention stabilizes light-weight articles as they are projected in-air from a conveyor belt for automated bulk processing equipment.
• the light-weight articles are stabilized along a conveyor belt from a first infeed end to a second discharge end.
• the off-belt stabilizing system provides a totally enclosed system that stabilizes the light-weight articles as they are projected in-air from the second discharge end of the conveyor belt.
• the air flow at and past the end of the belt is controlled by a hood structure so that light-weight articles that are projected within the air flow travel along a known and predictable trajectory.
• This invention also includes improved multi-spectral illumination and sensing of the articles, which is achieved by incorporating a pair of oppositely facing optical illuminating stations and a sorting station into the off-belt stabilizing system.
• Windows are provided in upper and lower surfaces of the hood structure through which the illumination stations provide red (“R"), green (“G”), and infrared (“IR”) illumination (or other wavelength combinations) of both major surfaces of the articles as they pass by an associated pair of line-scanning "color” cameras.
• Dichroic prisms render the cameras sensitive to the R, G, and IR wavelengths of the illumination stations.
• the windows extend between the illumination stations and the articles as they travel in-air through the stabilizing system and along their trajectory.
• R, G, and IR illumination provides sufficiently differing ratios of reflected
• R, G, and IR radiation that are usable for making reliable article classification sorting decisions for the above-described tobacco and other products.
• Fig. 1 is an isometric view of an automated bulk processing system with an off-belt stabilizing system and R, G, and IR illumination and detection system of this invention.
• Fig. 2 is a schematic side view of the automated bulk processing system of
• Fig. 3 is an enlarged sectional side view of an alternative infeed chute and associated components of an on-belt second stabilizing system shown in Fig. 1.
• Fig. 4 is an enlarged schematic side view of the off -belt stabilizing system and R, G, and IR illumination and detection system of this invention.
• Fig. 5 is a pictorial plan view of an R, G, and IR article illumination unit of this invention.
• Fig. 6 is a graphical representation of energy output spectrum produced by the article illumination unit of Fig. 5.
• Fig. 7 is a graphical representation of prior art R, G, and blue ("B") energy wavelengths reflected from good tobacco products and various defects.
• Fig. 8 is a graphical representation of R, G, and IR energy wavelengths reflected from good tobacco products and various defects in accordance with illumination and detection techniques of this invention.
• Figs. 9, 10, 11, and 12 are graphical representations of visible and IR wavelength reflectance curves for, respectively, tobacco products and stained latex, raisins and stems, good potato flesh and defects, and peach meat and peach pits.
• FIGs. 1 and 2 show an automated bulk optical processing system 10 of this invention that includes an on-belt stabilizing system 12 and an off-belt stabilizing system 14 for stabilizing articles carried by a conveyor 16.
• Optical processing system 10 is based on one described in copending U.S. Patent Application No. 08/657,357, filed June 3, 1998 for OFF-BELT STABILIZING SYSTEM FOR LIGHT-WEIGHT ARTICLES, which is assigned to the assignee of this application.
• Processing system 10 preferably performs optical inspection of large quantities of light-weight articles such as, for example, stripped-leaf tobacco or laminae, tobacco stems, re-claimed tobacco, wood chips, or light-weight debris.
• stabilizing systems 12 and 14 could be similarly employed by other types of automated processing equipment such as, for example, packaging systems.
• Conveyor 16 carries articles 17 (Fig. 2) on a commercially available antistatic belt 18 known and used by those having ordinary skill in the art. This type of belt reduces any static charge that may develop during operation. Static charge in belt 18 may cause articles 17 to adhere thereto and reduce the effectiveness of the system.
• Belt 18 forms a closed loop around a drive roller 20 and a spaced-apart, free-running end roller 22.
• a motor (not shown) coupled to drive roller 20 drives belt 18 such that an upper surface 24 moves at a velocity in a direction 26 toward off-belt stabilizing system 14 that includes upper and lower optical inspection stations 28 A and 28B and a sorting station 30.
• Articles 17 are delivered to belt 18 by an infeed system 46 that has an angled chute 48 down which articles 17 slide and are accelerated to about half the velocity of upper surface 24 of belt 18. Articles 17 slide off a lower end 50 of chute 48 and drop onto belt 18.
• Infeed system 46 could alternatively employ an infeed conveyor belt, and inactive chute, or a vibrating chute.
• On-belt stabilizing system 12 helps to accelerate articles 17 dropping from chute 48 to the speed of belt 18 by generating a flow 52 of fluid, preferably a readily available gas such as air, that passes between belt 18 and lower end 50 of chute 48.
• Air flow 52 engages articles 17 as they drop from chute 48 onto belt 18 and functions to accelerate the articles to the velocity of belt 18.
• Air flow 52 has a velocity that may, but need not, equal the velocity of belt 18. After articles 17 are accelerated to at or about the velocity of belt 18, air flow 52 functions to stabilize the articles on belt 18.
• on-belt stabilizing system 12 may alternatively employ a chamber or plenum 54 that receives pressurized air from a blower 56 via a conduit 57.
• a nozzle 58 in plenum 54 is positioned below and extends across chute 48 and belt 18 to provide a generally smooth flow 52 of air for stabilizing articles 17.
• Belt 18 carries the articles to off-belt stabilizing system 14 for processing.
• Infeed system 46 receives articles 17 at a receiving end 60 of chute 48 from an infeed shaker, conveyor belt, pin feeder, or the like (none shown). Articles 17 are accelerated by gravity as they slide along chute 48 through a bend 64 toward lower end 50.
• Chamber or plenum 54 is positioned below chute 48 and receives pressurized air from blower 56. Bend 64 in chute 48 cooperates with a slanted bottom surface 66 of plenum 54 to form nozzle 58 that extends across the width of belt 18.
• nozzle 58 forms an opening with a height 68 of about 0.25 in (0.64 cm).
• ionized air is preferably used to create the flow 52.
• the air is ionized by passing the air in plenum 54 across an ion bar 69 mounted in any desired fashion within the plenum 54.
• Ion bar 69 extends across the width of the belt 18 and is of the type known and used by those skilled in the art.
• On-belt stabilizing system 12 further includes a tunnel 70 that extends from an entrance 72 and along the length of and generally enclosing upper surface 24 of belt 18.
• Tunnel 70 allows stabilizing system 12 to form and propagate a flow 74 of fluid, preferably a readily available gas such as air, that passes over and past the length of belt 18.
• Tunnel 70 is formed by a hood 79 positioned over and extending along belt 18.
• any on-belt stabilizing system may be used to stabilize the light-weight articles on conveyor belt 18.
• a dual conveyor belt system such one used in the Tobacco Scan 6000 manufactured by
• Elbicon located near Brussels, Belgium may be used that employs a counter-rotating conveyor belt located above the lower article-bearing conveyor belt.
• the counter- rotating conveyor belt creates a flow of air between the lower conveyor belt and the counter-rotating conveyor belt to stabilize the articles on the lower conveyor belt.
• a conventional conveyor system not employing an air assisted stabilizing system only a thin boundary layer of air travels at or near the speed of the conveyor belt.
• the boundary layer typically extends only a few millimeters above the belt.
• Articles with thicknesses greater than a few millimeters extend through the boundary layer to slower or generally stagnant air.
• articles 17, or certain ones of them may be retarded by the slower- moving air, thereby destabilizing at least some of articles 17 on belt 18, causing them to roll, tumble, bounce or collide with one another.
• Air flow 74 induces an air draft along tunnel entrance 72 so that articles 17 carried on belt 18 are gradually stabilized by air flows of increasing velocity.
• On-belt stabilizing system 12 stabilizes articles 17 carried on belt 18 so that they are substantially stable and travel at substantially the belt velocity toward off-belt stabilizing system 14.
• off-belt stabilizing system 14 includes an end hood portion 80 that extends through inspection stations 28A and 28B and supports sorting station 30 to provide a closed environment for articles 17 as they are propelled off the end of belt 18.
• Inspection station 28A and 28B include respective upper and lower article illumination units 84 and 86 and upper and lower camera modules 88 and 90 to identify selected optical characteristics of articles 17 as they are propelled from belt 18.
• Upper and lower camera modules 88 and 90 include dichroic prisms that separate the wavelengths of light detected into R (600 to 700 ran), G (500 to 600 nm), and IR (700 to at least 900 nm) wavelength spectrum portions. Suitable prisms are available under specification drawing No. SSB-BA005-01 from Canon U.S.A., Inc., located in Irvine, California.
• Article illumination units 84 and 86 are rich in R, G, and IR spectral radiation and are described in more detail with reference to Figs. 4 and 5.
• Camera modules 88 and 90 view the articles along respective lines of sight 92 and 94 through adjustable mirrors 96 and 98.
• Inspection stations 28 A and 28B identify preselected ratios of R, G, and IR radiation reflected from articles 17 in accordance with methods and processing systems described in U.S. Patent No. 5,085,325 of Jones et al. for COLOR SORTING SYSTEM AND METHOD, which is assigned to the assignee of this application and incorporated herein by reference.
• Windows 100 and 102 are mounted within end hood portion 80.
• Windows 100 and 102 may be constructed of any durable transparent material, such as, for example, glass or plastic.
• Upper window 100 may be mounted by, for example, brackets 104 and fasteners 106.
• Lower window 102 may be secured by, for example, fasteners 107 to flanges 108 and 110 of end hood portion 80. These windows protect article illumination units 84 and 86 from articles 17 and from any other debris that may be included within the flow of articles.
• Article illumination units 84 and 86 are located substantially close to the lines of sight 92 and 94 of articles 17 without interfering with the field of view of cameras 88 and 90.
• Lines of sight 92 and 94 are offset from one another and may terminate at background lamps 111, which provide either a contrasting or noncontrasting background color for cameras 88 and 90 to view while inspecting radiation from upper and lower article illumination units 84 and 86 reflected off articles 17.
• Background lamps 111 are preferably fluorescent tubes providing a noncontrasting background color similar to the color of tobacco products.
• Cameras 88 and 90 view articles 17 along scan lines (shown end-on as X's) that extend transverse to direction 26 of travel of the belt 18.
• the scan lines have a length substantially the same as the width of belt 18 so that articles 17 anywhere along the width of belt 18 are viewed by cameras 88 and 90.
• Upper and lower article illumination units 84 and 86 are elongated and mounted to extend transverse to direction 26 of travel of belt 18 and are, therefore, parallel to scan lines X.
• Upper and lower article illumination units 84 and 86 cannot be exactly collinear with scan lines X because they would block the view of the cameras 88 and 90 and would cause specular reflections off windows 100 and 102 into the cameras.
• Upper and lower article illumination units 84 and 86 are substantially more collinear with the scan line than has been possible in prior systems. Thus, improved illumination of the articles 17 is provided. This placement of lamps relative to scan lines X causes focused radiation to illuminate articles 17 for the respective camera without interfering with the illumination for the other camera. Because light-weight articles, such as tobacco products, may be somewhat transparent, radiation transmitted through the articles can create false color indications. The preferred geometry and illumination source of this invention combine to solve the problem. Upper and lower article illumination units 84 and 86 are described in more detail with reference to Fig. 5.
• sorting station 30 employs multiple "puff jets" 112 positioned downstream of but substantially across the width of belt 18 to produce pressurized air blasts directed through an access opening (not shown) in end hood portion 80 to divert selected (typically defective) ones of articles 17, which would otherwise be propelled along normal trajectories 113 from belt 18.
• Defective articles 17 may be diverted by sorting station 30 into a defect chute A, thereby allowing acceptable articles to be propelled into an acceptance chute B.
• Air curtain unit 114 having an adjustable nozzle 116 is positioned below end roller 22 and directs an air flow 118 toward normal trajectories 113.
• Air flow 118 functions to support relatively small or light-weight articles within normal trajectories 113 and prevents the light-weight articles from being drawn around and under roller 22 by turbulent air flow.
• Air curtain 114 has a housing 120, a top 122 of which is horizontally adjustable by a rack 124 and pinion 126 that may be rotated either manually or by a motor (not shown) to adjust the nozzle opening 116 through which the air is directed and allows control of air flow 118.
• Air flow 118 further acts to clean lower window 102 of any debris or dust.
• an ion bar 128, similar to ion bar 69 employed within plenum 54, is located within air curtain unit 114.
• processing system 10 conveys, inspects, and sorts tobacco leaf products, wood chips, or debris with belt 18 having a width of 2-6 ft (0.6-1.8 m) and driven at a velocity of up to about 1,500 ft/min (7.6 m/sec).
• Stabilizing system 12 with nozzle 50 having a height of .25 in. (0.006 m) through which air flow 52 is driven at 10,000 ft/min (50.8 m/sec), displaces about 850 ft 3 /min (24.1 m 3 /min) (standard).
• Fig. 4 shows in a side, or end-on view of article illumination units 84 and 86
• Fig. 5 is a top view revealing internal components thereof.
• article illumination units 84 and 86 include an elongated, shallow box-shaped housing 150 that encloses a pair of 1000 watt cesium halide doped high-intensity discharge lamps 152 that are optically separated by a light baffle 154.
• Four elongated cylindrical lens assemblies 156 are spaced along an open side 158 of housing 150 to project an image of lamps 152 that extends substantially along scan lines X (Fig. 4) to illuminate articles 17 passing therethrough.
• Fig. 4 shows in a side, or end-on view of article illumination units 84 and 86
• Fig. 5 is a top view revealing internal components thereof.
• the side and top views together reveal that article illumination units 84 and 86 include an elongated, shallow box-shaped housing 150 that encloses a pair of 1000 watt cesium halide doped
• Spectrum 160 provides spectral energy that is suitably matched to the R, G, and IR wavelength sensitivities of camera modules 88 and 90 and which produces a spectral illumination of articles 17 that provides suitable contrast between good tobacco products and foreign materials.
• Camera modules 88 and 90 detect the spectral energy reflected from articles 17 and foreign materials and provide "pixel" signals representative of the reflected energy distributed along scan lines X.
• Camera modules 88 and 90 convert the reflectance values into voltages (0 to 1 volt) and analog-to-digital converters ("ADCs", not shown) generate binary numbers from the voltages (0 to 256 dec, 00 to FF hex) in direct proportion to reflectance value.
• ADCs analog-to-digital converters
• the hex values might be IE, 0C, 99 for the R, G, and IR signals respectively. This is formed into a binary address where the G 8 bits form the most significant portion of a 24-bit word and the IR 8 bits form the least significant portion of the 24-bit word.
• the resulting 24-bit word is applied as an address into a lookup table. Stored at the 24-bit address would be the a binary value "0" indicating a defect or a binary value "1 " indicating an acceptable article.
• These pixel by pixel lookup table decisions are grouped for size filtering and the appropriate puff jets 112 (Fig. 4) activated to deflect the defective articles down defect chute A (Fig. 4).
• Fig. 7 shows the spectral reflectance curves of good tobacco products 170 and various typical defects as detected in conventional R, G, and B (blue) inspection and sorting systems.
• this conventional spectral region there is insufficient distinction between the reflectances of black butyl defects 172 and good tobacco. Because of the typical 10% reflectance variations over large samples of articles, it is not surprising that black butyl defects 172 are difficult to separate from good tobacco products 170.
• Fig. 8 shows the spectral reflectance curves of good tobacco products 174 and various typical defects as detected in the R, G, and IR inspection and sorting system of this invention.
• a processor concatenates these values to form a binary address where the G 8 bits form the most significant portion of a 24-bit word and the IR 8 bits form the least significant portion of the 24-bit word.
• This 24-bit word is applied as an address into a lookup table. Stored at this address would be the binary value for "0" indicating that blue rope is a defect.
• the 24-bit word for black butyl defects 172 might be 07, 07, 07. At that address and in close proximity thereto, would be found the binary value "0" indicating that black butyl is also a defect.
• Good tobacco products 174 might have values of OF, 21, 66. At that address would be found a binary value "1 " indicating that good tobacco products 174 have been detected and should not be removed.
• Fig. 9 shows spectral reflectance curves suitable for separating good tobacco products 174 from stained latex
• Fig. 10 shows spectral reflectance curves suitable for separating raisins 186 from stems 188
• Fig. 11 shows spectral reflectance curves suitable for separating good potato flesh 190 from various defects 192
• Fig. 12 shows spectral reflectance curves suitable for separating peach meat 194 from pits 196 or fragments .of pit material.
• Fig. 12 further shows a short-wave IR spectral energy curve 198 generated by an indium iodide- doped lamp suitable for short-wavelength infrared illumination of articles in some applications of this invention.
• Cameras modules 88 and 90 need not be used in a dual configuration because a single camera can suitably inspect many articles, although dual cameras are preferred.
• a cold mirror could be inserted in lines of sight 92 and 94 for dividing at about 700 nm the reflected energy into separate visible and IR paths.
• Separate visible- and IR-sensitive cameras or sensors could be arranged to detect the energy in each path.

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• 2000
  • 2000-03-29 WO PCT/US2000/008384 patent/WO2000058035A1/en not_active Application Discontinuation
  • 2000-03-29 EP EP00918500A patent/EP1173292A4/de not_active Withdrawn
  • 2000-03-29 US US09/937,804 patent/US6646218B1/en not_active Expired - Fee Related
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